staging: wfx: make methods 'wfx_get_ps_timeout' and 'wfx_update_pm' static

Add "static" for local methods wfx_get_ps_timeout() and
wfx_update_pm() to address following sparse warnings.

wfx/sta.c:203:5: warning: symbol 'wfx_get_ps_timeout' was not declared. Should it be static?
wfx/sta.c:233:5: warning: symbol 'wfx_update_pm' was not declared. Should it be static?
Signed-off-by: Julius Hemanth Pitti <juliushemanth@gmail.com>
Link: https://lore.kernel.org/r/1591737854-11855-1-git-send-email-juliushemanth@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/wfx/sta.c

@@ -200,7 +200,7 @@ void wfx_configure_filter(struct ieee80211_hw *hw, unsigned int changed_flags,
 	mutex_unlock(&wdev->conf_mutex);
 }
 
-int wfx_get_ps_timeout(struct wfx_vif *wvif, bool *enable_ps)
+static int wfx_get_ps_timeout(struct wfx_vif *wvif, bool *enable_ps)
 {
 	struct ieee80211_channel *chan0 = NULL, *chan1 = NULL;
 	struct ieee80211_conf *conf = &wvif->wdev->hw->conf;
@@ -230,7 +230,7 @@ int wfx_get_ps_timeout(struct wfx_vif *wvif, bool *enable_ps)
 		return -1;
 }
 
-int wfx_update_pm(struct wfx_vif *wvif)
+static int wfx_update_pm(struct wfx_vif *wvif)
 {
 	int ps_timeout;
 	bool ps;